1. Field of the Invention
The invention relates to a clear, cosmetic and dermatological formulation with reduced stickiness.
2. Discussion of Background Information
For aesthetic reasons in particular, transparent and translucent products are preferred by many consumers. Thus, transparent formulations are often used, for example, as deodorant or antiperspirant (AP). These can nowadays be realized by the following technologies:                1. aqueous-alcoholic formulations        2. water-in-silicone emulsions        3. microemulsions        
The aqueous-alcoholic deodorant and AP formulations are mostly based on water and alcohol as medium, deodorant and antiperspirant agents as active ingredients, and also perfume, solubilizers and thickeners (mostly based on carbohydrate) as additional agents. They are perceived by the consumer as being fresh and cooling, but are at the same time encumbered with a whole series of disadvantages. Thus, for example, application primarily to freshly shaved skin is associated with incompatibilities as a result of the alcohol content. Another major disadvantage is the fact that relatively large amounts of oil cannot be incorporated into such systems. As a result of the high content of antiperspirant salt required for highly effective performance, a white residue remains following application to the skin; this is perceived by the consumer as being extremely troublesome. However, due to the absence of a sufficiently large oil phase for technical reasons, this cannot be concealed. Moreover, the use of carbohydrate thickeners leads to high stickiness of the product after the alcohol has evaporated.
Water-in-silicone emulsions belong to the group of water-in-oil emulsions. The water phase comprising ethanol or polyhydric alcohols, such as, for example, propylene glycol and water-soluble active ingredients, such as AP agent and/or deodorant active ingredient, constitutes about 75-90% of the formulation. The oil phase consists of a volatile and a nonvolatile silicone oil and also a silicone emulsifier.
The transparency of water-in-silicone emulsions is based on matching the refractive indices of the two phases. It is a drawback that even a difference in the indices of 0.0004 caused, for example, by evaporation, leads to cloudiness. WO 98/32418 and WO 92/05767 describe such deodorant or AP formulations based on W/Si emulsion.
One approach for solving the described disadvantages has been made possible through cosmetically pleasing alcohol-free and transparent products which are based on so-called microemulsions. These have the major advantage that even relatively large amounts of various oils—with all of the described positive effects for the consumer—can be stably incorporated. Formulations of this type are in principle available by means of phase inversion temperature technology (PIT) or high-pressure homogenization. The required stability of the emulsifier system to high concentrations of antiperspirant salts, however, places high demands on the formulation skill of the product developer.
WO 98/15255 describes microemulsions. However, a drawback even with these formulations is a sticky feel on the skin caused by the thickener, and the lack of a yield point.
It is an object of the present invention to provide a cosmetic preparation which enriches the prior art and helps to avoid its disadvantages.
In particular, it is the object of the present invention to provide a cosmetic and/or dermatological formulation which is transparent and is characterized by minimized stickiness. In particular, the object was to provide a deodorant or antiperspirant formulation which is transparent and has no cloudiness at all, which is characterized by a minimized stickiness and which has a defined yield point for optimized discharge and application.